git.oblomov.eu Git - linux-2.6/blob - net/sunrpc/rpc_pipe.c

   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/sysfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/config.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/mount.h>
  17 #include <linux/namei.h>
  18 #include <linux/dnotify.h>
  19 #include <linux/kernel.h>
  20
  21 #include <asm/ioctls.h>
  22 #include <linux/fs.h>
  23 #include <linux/poll.h>
  24 #include <linux/wait.h>
  25 #include <linux/seq_file.h>
  26
  27 #include <linux/sunrpc/clnt.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/sunrpc/rpc_pipe_fs.h>
  30
  31 static struct vfsmount *rpc_mount __read_mostly;
  32 static int rpc_mount_count;
  33
  34 static struct file_system_type rpc_pipe_fs_type;
  35
  36
  37 static kmem_cache_t *rpc_inode_cachep __read_mostly;
  38
  39 #define RPC_UPCALL_TIMEOUT (30*HZ)
  40
  41 static void
  42 __rpc_purge_upcall(struct inode *inode, int err)
  43 {
  44         struct rpc_inode *rpci = RPC_I(inode);
  45         struct rpc_pipe_msg *msg;
  46
  47         while (!list_empty(&rpci->pipe)) {
  48                 msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
  49                 list_del_init(&msg->list);
  50                 msg->errno = err;
  51                 rpci->ops->destroy_msg(msg);
  52         }
  53         while (!list_empty(&rpci->in_upcall)) {
  54                 msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
  55                 list_del_init(&msg->list);
  56                 msg->errno = err;
  57                 rpci->ops->destroy_msg(msg);
  58         }
  59         rpci->pipelen = 0;
  60         wake_up(&rpci->waitq);
  61 }
  62
  63 static void
  64 rpc_timeout_upcall_queue(void *data)
  65 {
  66         struct rpc_inode *rpci = (struct rpc_inode *)data;
  67         struct inode *inode = &rpci->vfs_inode;
  68
  69         down(&inode->i_sem);
  70         if (rpci->nreaders == 0 && !list_empty(&rpci->pipe))
  71                 __rpc_purge_upcall(inode, -ETIMEDOUT);
  72         up(&inode->i_sem);
  73 }
  74
  75 int
  76 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  77 {
  78         struct rpc_inode *rpci = RPC_I(inode);
  79         int res = 0;
  80
  81         down(&inode->i_sem);
  82         if (rpci->nreaders) {
  83                 list_add_tail(&msg->list, &rpci->pipe);
  84                 rpci->pipelen += msg->len;
  85         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
  86                 if (list_empty(&rpci->pipe))
  87                         schedule_delayed_work(&rpci->queue_timeout,
  88                                         RPC_UPCALL_TIMEOUT);
  89                 list_add_tail(&msg->list, &rpci->pipe);
  90                 rpci->pipelen += msg->len;
  91         } else
  92                 res = -EPIPE;
  93         up(&inode->i_sem);
  94         wake_up(&rpci->waitq);
  95         return res;
  96 }
  97
  98 static void
  99 rpc_close_pipes(struct inode *inode)
 100 {
 101         struct rpc_inode *rpci = RPC_I(inode);
 102
 103         cancel_delayed_work(&rpci->queue_timeout);
 104         flush_scheduled_work();
 105         down(&inode->i_sem);
 106         if (rpci->ops != NULL) {
 107                 rpci->nreaders = 0;
 108                 __rpc_purge_upcall(inode, -EPIPE);
 109                 rpci->nwriters = 0;
 110                 if (rpci->ops->release_pipe)
 111                         rpci->ops->release_pipe(inode);
 112                 rpci->ops = NULL;
 113         }
 114         up(&inode->i_sem);
 115 }
 116
 117 static inline void
 118 rpc_inode_setowner(struct inode *inode, void *private)
 119 {
 120         RPC_I(inode)->private = private;
 121 }
 122
 123 static struct inode *
 124 rpc_alloc_inode(struct super_block *sb)
 125 {
 126         struct rpc_inode *rpci;
 127         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, SLAB_KERNEL);
 128         if (!rpci)
 129                 return NULL;
 130         return &rpci->vfs_inode;
 131 }
 132
 133 static void
 134 rpc_destroy_inode(struct inode *inode)
 135 {
 136         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 137 }
 138
 139 static int
 140 rpc_pipe_open(struct inode *inode, struct file *filp)
 141 {
 142         struct rpc_inode *rpci = RPC_I(inode);
 143         int res = -ENXIO;
 144
 145         down(&inode->i_sem);
 146         if (rpci->ops != NULL) {
 147                 if (filp->f_mode & FMODE_READ)
 148                         rpci->nreaders ++;
 149                 if (filp->f_mode & FMODE_WRITE)
 150                         rpci->nwriters ++;
 151                 res = 0;
 152         }
 153         up(&inode->i_sem);
 154         return res;
 155 }
 156
 157 static int
 158 rpc_pipe_release(struct inode *inode, struct file *filp)
 159 {
 160         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 161         struct rpc_pipe_msg *msg;
 162
 163         down(&inode->i_sem);
 164         if (rpci->ops == NULL)
 165                 goto out;
 166         msg = (struct rpc_pipe_msg *)filp->private_data;
 167         if (msg != NULL) {
 168                 msg->errno = -EPIPE;
 169                 list_del_init(&msg->list);
 170                 rpci->ops->destroy_msg(msg);
 171         }
 172         if (filp->f_mode & FMODE_WRITE)
 173                 rpci->nwriters --;
 174         if (filp->f_mode & FMODE_READ)
 175                 rpci->nreaders --;
 176         if (!rpci->nreaders)
 177                 __rpc_purge_upcall(inode, -EPIPE);
 178         if (rpci->ops->release_pipe)
 179                 rpci->ops->release_pipe(inode);
 180         if (!rpci->nreaders && !rpci->nwriters)
 181                 rpci->ops = NULL;
 182 out:
 183         up(&inode->i_sem);
 184         return 0;
 185 }
 186
 187 static ssize_t
 188 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 189 {
 190         struct inode *inode = filp->f_dentry->d_inode;
 191         struct rpc_inode *rpci = RPC_I(inode);
 192         struct rpc_pipe_msg *msg;
 193         int res = 0;
 194
 195         down(&inode->i_sem);
 196         if (rpci->ops == NULL) {
 197                 res = -EPIPE;
 198                 goto out_unlock;
 199         }
 200         msg = filp->private_data;
 201         if (msg == NULL) {
 202                 if (!list_empty(&rpci->pipe)) {
 203                         msg = list_entry(rpci->pipe.next,
 204                                         struct rpc_pipe_msg,
 205                                         list);
 206                         list_move(&msg->list, &rpci->in_upcall);
 207                         rpci->pipelen -= msg->len;
 208                         filp->private_data = msg;
 209                         msg->copied = 0;
 210                 }
 211                 if (msg == NULL)
 212                         goto out_unlock;
 213         }
 214         /* NOTE: it is up to the callback to update msg->copied */
 215         res = rpci->ops->upcall(filp, msg, buf, len);
 216         if (res < 0 || msg->len == msg->copied) {
 217                 filp->private_data = NULL;
 218                 list_del_init(&msg->list);
 219                 rpci->ops->destroy_msg(msg);
 220         }
 221 out_unlock:
 222         up(&inode->i_sem);
 223         return res;
 224 }
 225
 226 static ssize_t
 227 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 228 {
 229         struct inode *inode = filp->f_dentry->d_inode;
 230         struct rpc_inode *rpci = RPC_I(inode);
 231         int res;
 232
 233         down(&inode->i_sem);
 234         res = -EPIPE;
 235         if (rpci->ops != NULL)
 236                 res = rpci->ops->downcall(filp, buf, len);
 237         up(&inode->i_sem);
 238         return res;
 239 }
 240
 241 static unsigned int
 242 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 243 {
 244         struct rpc_inode *rpci;
 245         unsigned int mask = 0;
 246
 247         rpci = RPC_I(filp->f_dentry->d_inode);
 248         poll_wait(filp, &rpci->waitq, wait);
 249
 250         mask = POLLOUT | POLLWRNORM;
 251         if (rpci->ops == NULL)
 252                 mask |= POLLERR | POLLHUP;
 253         if (!list_empty(&rpci->pipe))
 254                 mask |= POLLIN | POLLRDNORM;
 255         return mask;
 256 }
 257
 258 static int
 259 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 260                 unsigned int cmd, unsigned long arg)
 261 {
 262         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 263         int len;
 264
 265         switch (cmd) {
 266         case FIONREAD:
 267                 if (rpci->ops == NULL)
 268                         return -EPIPE;
 269                 len = rpci->pipelen;
 270                 if (filp->private_data) {
 271                         struct rpc_pipe_msg *msg;
 272                         msg = (struct rpc_pipe_msg *)filp->private_data;
 273                         len += msg->len - msg->copied;
 274                 }
 275                 return put_user(len, (int __user *)arg);
 276         default:
 277                 return -EINVAL;
 278         }
 279 }
 280
 281 static struct file_operations rpc_pipe_fops = {
 282         .owner          = THIS_MODULE,
 283         .llseek         = no_llseek,
 284         .read           = rpc_pipe_read,
 285         .write          = rpc_pipe_write,
 286         .poll           = rpc_pipe_poll,
 287         .ioctl          = rpc_pipe_ioctl,
 288         .open           = rpc_pipe_open,
 289         .release        = rpc_pipe_release,
 290 };
 291
 292 static int
 293 rpc_show_info(struct seq_file *m, void *v)
 294 {
 295         struct rpc_clnt *clnt = m->private;
 296
 297         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 298         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 299                         clnt->cl_prog, clnt->cl_vers);
 300         seq_printf(m, "address: %u.%u.%u.%u\n",
 301                         NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
 302         seq_printf(m, "protocol: %s\n",
 303                         clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
 304         return 0;
 305 }
 306
 307 static int
 308 rpc_info_open(struct inode *inode, struct file *file)
 309 {
 310         struct rpc_clnt *clnt;
 311         int ret = single_open(file, rpc_show_info, NULL);
 312
 313         if (!ret) {
 314                 struct seq_file *m = file->private_data;
 315                 down(&inode->i_sem);
 316                 clnt = RPC_I(inode)->private;
 317                 if (clnt) {
 318                         atomic_inc(&clnt->cl_users);
 319                         m->private = clnt;
 320                 } else {
 321                         single_release(inode, file);
 322                         ret = -EINVAL;
 323                 }
 324                 up(&inode->i_sem);
 325         }
 326         return ret;
 327 }
 328
 329 static int
 330 rpc_info_release(struct inode *inode, struct file *file)
 331 {
 332         struct seq_file *m = file->private_data;
 333         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 334
 335         if (clnt)
 336                 rpc_release_client(clnt);
 337         return single_release(inode, file);
 338 }
 339
 340 static struct file_operations rpc_info_operations = {
 341         .owner          = THIS_MODULE,
 342         .open           = rpc_info_open,
 343         .read           = seq_read,
 344         .llseek         = seq_lseek,
 345         .release        = rpc_info_release,
 346 };
 347
 348
 349 /*
 350  * We have a single directory with 1 node in it.
 351  */
 352 enum {
 353         RPCAUTH_Root = 1,
 354         RPCAUTH_lockd,
 355         RPCAUTH_mount,
 356         RPCAUTH_nfs,
 357         RPCAUTH_portmap,
 358         RPCAUTH_statd,
 359         RPCAUTH_RootEOF
 360 };
 361
 362 /*
 363  * Description of fs contents.
 364  */
 365 struct rpc_filelist {
 366         char *name;
 367         struct file_operations *i_fop;
 368         int mode;
 369 };
 370
 371 static struct rpc_filelist files[] = {
 372         [RPCAUTH_lockd] = {
 373                 .name = "lockd",
 374                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 375         },
 376         [RPCAUTH_mount] = {
 377                 .name = "mount",
 378                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 379         },
 380         [RPCAUTH_nfs] = {
 381                 .name = "nfs",
 382                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 383         },
 384         [RPCAUTH_portmap] = {
 385                 .name = "portmap",
 386                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 387         },
 388         [RPCAUTH_statd] = {
 389                 .name = "statd",
 390                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 391         },
 392 };
 393
 394 enum {
 395         RPCAUTH_info = 2,
 396         RPCAUTH_EOF
 397 };
 398
 399 static struct rpc_filelist authfiles[] = {
 400         [RPCAUTH_info] = {
 401                 .name = "info",
 402                 .i_fop = &rpc_info_operations,
 403                 .mode = S_IFREG | S_IRUSR,
 404         },
 405 };
 406
 407 static int
 408 rpc_get_mount(void)
 409 {
 410         return simple_pin_fs("rpc_pipefs", &rpc_mount, &rpc_mount_count);
 411 }
 412
 413 static void
 414 rpc_put_mount(void)
 415 {
 416         simple_release_fs(&rpc_mount, &rpc_mount_count);
 417 }
 418
 419 static int
 420 rpc_lookup_parent(char *path, struct nameidata *nd)
 421 {
 422         if (path[0] == '\0')
 423                 return -ENOENT;
 424         if (rpc_get_mount()) {
 425                 printk(KERN_WARNING "%s: %s failed to mount "
 426                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 427                 return -ENODEV;
 428         }
 429         nd->mnt = mntget(rpc_mount);
 430         nd->dentry = dget(rpc_mount->mnt_root);
 431         nd->last_type = LAST_ROOT;
 432         nd->flags = LOOKUP_PARENT;
 433         nd->depth = 0;
 434
 435         if (path_walk(path, nd)) {
 436                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 437                                 __FILE__, __FUNCTION__, path);
 438                 rpc_put_mount();
 439                 return -ENOENT;
 440         }
 441         return 0;
 442 }
 443
 444 static void
 445 rpc_release_path(struct nameidata *nd)
 446 {
 447         path_release(nd);
 448         rpc_put_mount();
 449 }
 450
 451 static struct inode *
 452 rpc_get_inode(struct super_block *sb, int mode)
 453 {
 454         struct inode *inode = new_inode(sb);
 455         if (!inode)
 456                 return NULL;
 457         inode->i_mode = mode;
 458         inode->i_uid = inode->i_gid = 0;
 459         inode->i_blksize = PAGE_CACHE_SIZE;
 460         inode->i_blocks = 0;
 461         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 462         switch(mode & S_IFMT) {
 463                 case S_IFDIR:
 464                         inode->i_fop = &simple_dir_operations;
 465                         inode->i_op = &simple_dir_inode_operations;
 466                         inode->i_nlink++;
 467                 default:
 468                         break;
 469         }
 470         return inode;
 471 }
 472
 473 /*
 474  * FIXME: This probably has races.
 475  */
 476 static void
 477 rpc_depopulate(struct dentry *parent)
 478 {
 479         struct inode *dir = parent->d_inode;
 480         struct list_head *pos, *next;
 481         struct dentry *dentry, *dvec[10];
 482         int n = 0;
 483
 484         down(&dir->i_sem);
 485 repeat:
 486         spin_lock(&dcache_lock);
 487         list_for_each_safe(pos, next, &parent->d_subdirs) {
 488                 dentry = list_entry(pos, struct dentry, d_child);
 489                 spin_lock(&dentry->d_lock);
 490                 if (!d_unhashed(dentry)) {
 491                         dget_locked(dentry);
 492                         __d_drop(dentry);
 493                         spin_unlock(&dentry->d_lock);
 494                         dvec[n++] = dentry;
 495                         if (n == ARRAY_SIZE(dvec))
 496                                 break;
 497                 } else
 498                         spin_unlock(&dentry->d_lock);
 499         }
 500         spin_unlock(&dcache_lock);
 501         if (n) {
 502                 do {
 503                         dentry = dvec[--n];
 504                         if (dentry->d_inode) {
 505                                 rpc_close_pipes(dentry->d_inode);
 506                                 rpc_inode_setowner(dentry->d_inode, NULL);
 507                                 simple_unlink(dir, dentry);
 508                         }
 509                         dput(dentry);
 510                 } while (n);
 511                 goto repeat;
 512         }
 513         up(&dir->i_sem);
 514 }
 515
 516 static int
 517 rpc_populate(struct dentry *parent,
 518                 struct rpc_filelist *files,
 519                 int start, int eof)
 520 {
 521         struct inode *inode, *dir = parent->d_inode;
 522         void *private = RPC_I(dir)->private;
 523         struct dentry *dentry;
 524         int mode, i;
 525
 526         down(&dir->i_sem);
 527         for (i = start; i < eof; i++) {
 528                 dentry = d_alloc_name(parent, files[i].name);
 529                 if (!dentry)
 530                         goto out_bad;
 531                 mode = files[i].mode;
 532                 inode = rpc_get_inode(dir->i_sb, mode);
 533                 if (!inode) {
 534                         dput(dentry);
 535                         goto out_bad;
 536                 }
 537                 inode->i_ino = i;
 538                 if (files[i].i_fop)
 539                         inode->i_fop = files[i].i_fop;
 540                 if (private)
 541                         rpc_inode_setowner(inode, private);
 542                 if (S_ISDIR(mode))
 543                         dir->i_nlink++;
 544                 d_add(dentry, inode);
 545         }
 546         up(&dir->i_sem);
 547         return 0;
 548 out_bad:
 549         up(&dir->i_sem);
 550         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 551                         __FILE__, __FUNCTION__, parent->d_name.name);
 552         return -ENOMEM;
 553 }
 554
 555 static int
 556 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 557 {
 558         struct inode *inode;
 559
 560         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
 561         if (!inode)
 562                 goto out_err;
 563         inode->i_ino = iunique(dir->i_sb, 100);
 564         d_instantiate(dentry, inode);
 565         dir->i_nlink++;
 566         inode_dir_notify(dir, DN_CREATE);
 567         rpc_get_mount();
 568         return 0;
 569 out_err:
 570         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 571                         __FILE__, __FUNCTION__, dentry->d_name.name);
 572         return -ENOMEM;
 573 }
 574
 575 static int
 576 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 577 {
 578         int error;
 579
 580         shrink_dcache_parent(dentry);
 581         if (dentry->d_inode) {
 582                 rpc_close_pipes(dentry->d_inode);
 583                 rpc_inode_setowner(dentry->d_inode, NULL);
 584         }
 585         if ((error = simple_rmdir(dir, dentry)) != 0)
 586                 return error;
 587         if (!error) {
 588                 inode_dir_notify(dir, DN_DELETE);
 589                 d_drop(dentry);
 590                 rpc_put_mount();
 591         }
 592         return 0;
 593 }
 594
 595 static struct dentry *
 596 rpc_lookup_negative(char *path, struct nameidata *nd)
 597 {
 598         struct dentry *dentry;
 599         struct inode *dir;
 600         int error;
 601
 602         if ((error = rpc_lookup_parent(path, nd)) != 0)
 603                 return ERR_PTR(error);
 604         dir = nd->dentry->d_inode;
 605         down(&dir->i_sem);
 606         dentry = lookup_hash(&nd->last, nd->dentry);
 607         if (IS_ERR(dentry))
 608                 goto out_err;
 609         if (dentry->d_inode) {
 610                 dput(dentry);
 611                 dentry = ERR_PTR(-EEXIST);
 612                 goto out_err;
 613         }
 614         return dentry;
 615 out_err:
 616         up(&dir->i_sem);
 617         rpc_release_path(nd);
 618         return dentry;
 619 }
 620
 621
 622 struct dentry *
 623 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 624 {
 625         struct nameidata nd;
 626         struct dentry *dentry;
 627         struct inode *dir;
 628         int error;
 629
 630         dentry = rpc_lookup_negative(path, &nd);
 631         if (IS_ERR(dentry))
 632                 return dentry;
 633         dir = nd.dentry->d_inode;
 634         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 635                 goto err_dput;
 636         RPC_I(dentry->d_inode)->private = rpc_client;
 637         error = rpc_populate(dentry, authfiles,
 638                         RPCAUTH_info, RPCAUTH_EOF);
 639         if (error)
 640                 goto err_depopulate;
 641 out:
 642         up(&dir->i_sem);
 643         rpc_release_path(&nd);
 644         return dentry;
 645 err_depopulate:
 646         rpc_depopulate(dentry);
 647         __rpc_rmdir(dir, dentry);
 648 err_dput:
 649         dput(dentry);
 650         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 651                         __FILE__, __FUNCTION__, path, error);
 652         dentry = ERR_PTR(error);
 653         goto out;
 654 }
 655
 656 int
 657 rpc_rmdir(char *path)
 658 {
 659         struct nameidata nd;
 660         struct dentry *dentry;
 661         struct inode *dir;
 662         int error;
 663
 664         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 665                 return error;
 666         dir = nd.dentry->d_inode;
 667         down(&dir->i_sem);
 668         dentry = lookup_hash(&nd.last, nd.dentry);
 669         if (IS_ERR(dentry)) {
 670                 error = PTR_ERR(dentry);
 671                 goto out_release;
 672         }
 673         rpc_depopulate(dentry);
 674         error = __rpc_rmdir(dir, dentry);
 675         dput(dentry);
 676 out_release:
 677         up(&dir->i_sem);
 678         rpc_release_path(&nd);
 679         return error;
 680 }
 681
 682 struct dentry *
 683 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
 684 {
 685         struct nameidata nd;
 686         struct dentry *dentry;
 687         struct inode *dir, *inode;
 688         struct rpc_inode *rpci;
 689
 690         dentry = rpc_lookup_negative(path, &nd);
 691         if (IS_ERR(dentry))
 692                 return dentry;
 693         dir = nd.dentry->d_inode;
 694         inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
 695         if (!inode)
 696                 goto err_dput;
 697         inode->i_ino = iunique(dir->i_sb, 100);
 698         inode->i_fop = &rpc_pipe_fops;
 699         d_instantiate(dentry, inode);
 700         rpci = RPC_I(inode);
 701         rpci->private = private;
 702         rpci->flags = flags;
 703         rpci->ops = ops;
 704         inode_dir_notify(dir, DN_CREATE);
 705 out:
 706         up(&dir->i_sem);
 707         rpc_release_path(&nd);
 708         return dentry;
 709 err_dput:
 710         dput(dentry);
 711         dentry = ERR_PTR(-ENOMEM);
 712         printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
 713                         __FILE__, __FUNCTION__, path, -ENOMEM);
 714         goto out;
 715 }
 716
 717 int
 718 rpc_unlink(char *path)
 719 {
 720         struct nameidata nd;
 721         struct dentry *dentry;
 722         struct inode *dir;
 723         int error;
 724
 725         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 726                 return error;
 727         dir = nd.dentry->d_inode;
 728         down(&dir->i_sem);
 729         dentry = lookup_hash(&nd.last, nd.dentry);
 730         if (IS_ERR(dentry)) {
 731                 error = PTR_ERR(dentry);
 732                 goto out_release;
 733         }
 734         d_drop(dentry);
 735         if (dentry->d_inode) {
 736                 rpc_close_pipes(dentry->d_inode);
 737                 rpc_inode_setowner(dentry->d_inode, NULL);
 738                 error = simple_unlink(dir, dentry);
 739         }
 740         dput(dentry);
 741         inode_dir_notify(dir, DN_DELETE);
 742 out_release:
 743         up(&dir->i_sem);
 744         rpc_release_path(&nd);
 745         return error;
 746 }
 747
 748 /*
 749  * populate the filesystem
 750  */
 751 static struct super_operations s_ops = {
 752         .alloc_inode    = rpc_alloc_inode,
 753         .destroy_inode  = rpc_destroy_inode,
 754         .statfs         = simple_statfs,
 755 };
 756
 757 #define RPCAUTH_GSSMAGIC 0x67596969
 758
 759 static int
 760 rpc_fill_super(struct super_block *sb, void *data, int silent)
 761 {
 762         struct inode *inode;
 763         struct dentry *root;
 764
 765         sb->s_blocksize = PAGE_CACHE_SIZE;
 766         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 767         sb->s_magic = RPCAUTH_GSSMAGIC;
 768         sb->s_op = &s_ops;
 769         sb->s_time_gran = 1;
 770
 771         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 772         if (!inode)
 773                 return -ENOMEM;
 774         root = d_alloc_root(inode);
 775         if (!root) {
 776                 iput(inode);
 777                 return -ENOMEM;
 778         }
 779         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 780                 goto out;
 781         sb->s_root = root;
 782         return 0;
 783 out:
 784         d_genocide(root);
 785         dput(root);
 786         return -ENOMEM;
 787 }
 788
 789 static struct super_block *
 790 rpc_get_sb(struct file_system_type *fs_type,
 791                 int flags, const char *dev_name, void *data)
 792 {
 793         return get_sb_single(fs_type, flags, data, rpc_fill_super);
 794 }
 795
 796 static struct file_system_type rpc_pipe_fs_type = {
 797         .owner          = THIS_MODULE,
 798         .name           = "rpc_pipefs",
 799         .get_sb         = rpc_get_sb,
 800         .kill_sb        = kill_litter_super,
 801 };
 802
 803 static void
 804 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 805 {
 806         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 807
 808         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 809             SLAB_CTOR_CONSTRUCTOR) {
 810                 inode_init_once(&rpci->vfs_inode);
 811                 rpci->private = NULL;
 812                 rpci->nreaders = 0;
 813                 rpci->nwriters = 0;
 814                 INIT_LIST_HEAD(&rpci->in_upcall);
 815                 INIT_LIST_HEAD(&rpci->pipe);
 816                 rpci->pipelen = 0;
 817                 init_waitqueue_head(&rpci->waitq);
 818                 INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
 819                 rpci->ops = NULL;
 820         }
 821 }
 822
 823 int register_rpc_pipefs(void)
 824 {
 825         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 826                                              sizeof(struct rpc_inode),
 827                                              0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
 828                                              init_once, NULL);
 829         if (!rpc_inode_cachep)
 830                 return -ENOMEM;
 831         register_filesystem(&rpc_pipe_fs_type);
 832         return 0;
 833 }
 834
 835 void unregister_rpc_pipefs(void)
 836 {
 837         if (kmem_cache_destroy(rpc_inode_cachep))
 838                 printk(KERN_WARNING "RPC: unable to free inode cache\n");
 839         unregister_filesystem(&rpc_pipe_fs_type);
 840 }